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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * The Universal Permissive License (UPL), Version 1.0
 *
 * Subject to the condition set forth below, permission is hereby granted to any
 * person obtaining a copy of this software, associated documentation and/or
 * data (collectively the "Software"), free of charge and under any and all
 * copyright rights in the Software, and any and all patent rights owned or
 * freely licensable by each licensor hereunder covering either (i) the
 * unmodified Software as contributed to or provided by such licensor, or (ii)
 * the Larger Works (as defined below), to deal in both
 *
 * (a) the Software, and
 *
 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
 * is contributed by such licensors),
 *
 * without restriction, including without limitation the rights to copy, create
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 * use, sell, offer for sale, import, export, have made, and have sold the
 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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package com.oracle.truffle.api.bytecode;

import java.lang.reflect.Field;

import com.oracle.truffle.api.frame.FrameExtensions;
import com.oracle.truffle.api.memory.ByteArraySupport;

import sun.misc.Unsafe;

/**
 * Implementation of BytecodeDSLAccess that uses Unsafe.
 */
@SuppressWarnings("deprecation")
final class BytecodeDSLUncheckedAccess extends BytecodeDSLAccess {

    static final Unsafe UNSAFE = initUnsafe();

    private static Unsafe initUnsafe() {
        try {
            // Fast path when we are trusted.
            return Unsafe.getUnsafe();
        } catch (SecurityException se) {
            // Slow path when we are not trusted.
            try {
                Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
                theUnsafe.setAccessible(true);
                return (Unsafe) theUnsafe.get(Unsafe.class);
            } catch (Exception e) {
                throw new RuntimeException("exception while trying to get Unsafe", e);
            }
        }
    }

    @Override
    public FrameExtensions getFrameExtensions() {
        return BytecodeAccessor.RUNTIME.getFrameExtensionsUnsafe();
    }

    @Override
    public ByteArraySupport getByteArraySupport() {
        return BytecodeAccessor.MEMORY.getNativeUnsafe();
    }

    @Override
    public int readInt(int[] arr, int index) {
        assert index >= 0 && index < arr.length;
        return UNSAFE.getInt(arr, Unsafe.ARRAY_INT_BASE_OFFSET + index * Unsafe.ARRAY_INT_INDEX_SCALE);
    }

    @Override
    public void writeInt(int[] arr, int index, int value) {
        assert index >= 0 && index < arr.length;
        UNSAFE.putInt(arr, Unsafe.ARRAY_INT_BASE_OFFSET + index * Unsafe.ARRAY_INT_INDEX_SCALE, value);
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> T readObject(T[] arr, int index) {
        assert index >= 0 && index < arr.length;
        return (T) UNSAFE.getObject(arr, Unsafe.ARRAY_OBJECT_BASE_OFFSET + index * Unsafe.ARRAY_OBJECT_INDEX_SCALE);
    }

    @Override
    public <T> void writeObject(T[] arr, int index, T value) {
        assert index >= 0 && index < arr.length;
        UNSAFE.putObject(arr, Unsafe.ARRAY_OBJECT_BASE_OFFSET + index * Unsafe.ARRAY_OBJECT_INDEX_SCALE, value);
    }

    @Override
    @SuppressWarnings("unchecked")
    public <T> T uncheckedCast(Object obj, Class<T> clazz) {
        return (T) obj;
    }

}
